Lessons from the Evolution of the Automated External Defibrillator

Not too many years ago, the chances of surviving a sudden cardiac event outside of a hospital setting were slim. Realizing the need for a life-saving treatment that could be used almost anywhere, and by almost anyone, the Royal Victoria Hospital-Belfast, under the direction of Dr. Frank Pantridge and Dr. Geddes, launched the world’s first mobile coronary care unit, which included the world’s first portable defibrillator. The research team, which formed the company, HeartSine in 1988, now owned by Stryker, continued to refine the device to make it more lightweight and portable. The Ulster University academics have since gone from a team of five employees to being acquired by one of the world’s largest medtech companies by a process of constantly refining and improving their devices.

“Much of our early work was focused on the development of suitable technology to allow this miniaturization to be realized,” Finlay explained. “These developments, including the integration and in-house research of new flat-panel displays, compact capacitors, flexible defibrillator pads, high-density batteries, and embedded software, primarily led to a device that was suitable for transportation in an ambulance to a patient suspected of having a cardiac arrest.”

This work provided the platform for which the modern wall-mounted automated external defibrillator (AED) is based on, Finlay said. HeartSine’s flagship product, the HeartSine Samaritan public access defibrillator (PAD; pictured above), has been deployed in thousands of facilities in more than 70 companies and in more than 30 languages.

The evolution of the device was based on many years of experience, explained Professor James McLaughlin, Head of School of Engineering, Ulster University. “As with all of Ulster University’s work in medical devices and related technology development, we have learned that many iterations of the technology are required to facilitate a final viable solution,” he explained.


Incremental Gains in Response Time with Varying Base Location Types for Drone-Delivered Automated External Defibrillators

Introduction: Drone-delivered automated external defibrillators (AEDs) may reduce delays to defibrillation for out-of-hospital cardiac arrests (OHCAs). We sought to determine how integration of drones and selection of drone bases between emergency service stations (i.e., paramedic, fire, police) would affect 9-1-1 call-to-arrival intervals.

Methods: We identified all treated OHCAs in southern Vancouver Island, British Columbia, Canada from Jan. 2014 to Dec. 2020. We developed mathematical models to select 1-5 optimal drone base locations from each of: paramedic stations, fire stations, police stations, or an unrestricted grid-based set of points to minimize drone travel time to OHCAs. We evaluated models on the estimated first response interval assuming that drones were integrated with existing OHCA response. We compared median response intervals with historical response, as well as across drone base locations.

Results: A total of 1,610 OHCAs were included in the study with a historical median response interval of 6.4 minutes (IQR 5.0-8.6). All drone-integrated response systems significantly reduced the median response interval to 4.2-5.4 minutes (all P<0.001), with grid-based stations using 5 drones resulting in the lowest response interval (4.2 minutes). Median response times between drone base location types differed by 6-16 seconds, all comparisons of which were statistically significant (all P<0.02).

Conclusion: Integrating drone-delivered AEDs into OHCA response may reduce first response intervals, even with a small quantity of drones. Implementing drone response with only one emergency service resulted in similar response metrics regardless of the emergency service hosting the drone base and was competitive with unrestricted drone base locations.


Understanding the Importance of the Lay Responder Experience in Out-of-Hospital Cardiac Arrest: A Scientific Statement From the American Heart Association

Bystander cardiopulmonary resuscitation (CPR) is critical to increasing survival from out-of-hospital cardiac arrest. However, the percentage of cases in which an individual receives bystander CPR is actually low, at only 35% to 40% globally. Preparing lay responders to recognize the signs of sudden cardiac arrest, call 9-1-1, and perform CPR in public and private locations is crucial to increasing survival from this public health problem. The objective of this scientific statement is to summarize the most recent published evidence about the lay responder experience of training, responding, and dealing with the residual impact of witnessing an out-of-hospital cardiac arrest. The scientific statement focuses on the experience-based literature of actual responders, which includes barriers to responding, experiences of doing CPR, use of an automated external defibrillator, the impact of dispatcher-assisted CPR, and the potential for postevent psychological sequelae. The large body of qualitative and observational studies identifies several gaps in crucial knowledge that, if targeted, could increase the likelihood that those who are trained in CPR will act. We suggest using the experience of actual responders to inform more contextualized training, including the implications of performing CPR on a family member, dispelling myths about harm, training and litigation, and recognition of the potential for psychologic sequelae after the event.



Cardiopulmonary Resuscitation and Defibrillator Use in Sports

Sudden cardiac arrest (SCA) in young athletes is rare, with an estimated incidence ranging from 0.1 to 2 per 100,000 per athlete year. The creation of SCA registries can help provide accurate data regarding incidence, treatment, and outcomes and help implement primary or secondary prevention strategies that could change the course of these events.

 Early cardiopulmonary resuscitation (CPR) and defibrillation are the most important determinants of survival and neurological prognosis in individuals who suffer from SCA. Compared with the general population, individuals with clinically silent cardiac disease who practice regular physical exercise are at increased risk of SCA events. While the implementation of national preparticipation screening has been largely debated, with no current consensus, the number of athletes who will be diagnosed with cardiac disease and have an indication for implantable defibrillator cardioverter defibrillator (ICD) is unknown. Many victims of SCA do not have a previous cardiac diagnosis.

Therefore, the appropriate use and availability of automated external defibrillators (AEDs) in public spaces is the crucial part of the integrated response to prevent these fatalities both for participating athletes and for spectators. Governments and sports institutions should invest and educate members of the public, security, and healthcare professionals in immediate initiation of CPR and early AED use. Smartphone apps could play an integral part to allow bystanders to alert the emergency services and CPR trained responders and locate and utilize the nearest AED to positively influence the outcomes by strengthening the chain of survival. This review aims to summarize the available evidence on sudden cardiac death prevention among young athletes and to provide some guidance on strategies that can be implemented by governments and on the novel tools that can help save these lives.


The PHOENIX: Design and Development of a Three-Dimensional-Printed Drone Prototype and Corresponding Simulation Scenario Based on the Management of Cardiac Arrest

Sudden cardiac arrest (SCA) remains one of the most prevalent cardiovascular emergencies in the world. The development of international protocols and the use of accessible devices such as automated external defibrillators (AEDs) allowed for the standardization and organization of medical care related to SCA. When defibrillation is performed within five minutes of starting ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT), the victim survival rate has increased considerably. 

Therefore, training healthcare professionals to use AEDs correctly is essential to improve patient outcomes and response time in the intervention. In this technical report, we advocate simulation-based education as a teaching methodology and an essential component of drone adaptation, novel technology, that can deliver AEDs to the site, as well as a training scenario to teach healthcare professionals how to operate the real-time communication components of drones and AEDs efficiently.

Studies have suggested that simulation can be an effective way to train healthcare professionals. Through teaching methodology using simulation, training these audiences has the potential to reduce the response time to intervention, consequently, increasing the patient’s chance of surviving.


The Association of Fire or Police First Responder Initiated Interventions with Out of Hospital Cardiac Arrest Survival

Fire and police first responders are often the first to arrive in medical emergencies and provide basic life support services until specialized personnel arrive. This study aims to evaluate rates of fire or police first responder-initiated cardiopulmonary resuscitation (CPR) and automated external defibrillator (AED) use, as well as their associated impact on out-of-hospital cardiac arrest (OHCA) outcomes.

Results: Our cohort included 25,067 OHCA incidents. We found fire or police first responders initiated CPR in 31.8% of OHCA events and AED use in 6.1% of OHCA events. Likelihood of sustained ROSC on ED arrival after CPR initiated by a fire/police first responder was not statistically different as compared to EMS initiated CPR (aOR 1.01, CI 0.93-1.11). However, fire/police first responder interventions were associated with significantly higher odds of survival to hospital discharge and survival with good neurologic outcome (aOR 1.25, 95% CI 1.08-1.45 and aOR 1.40, 95% CI 1.18-1.65, respectively). Similar associations were see when examining fire or police initiated AED use.

Conclusions: Fire or police first responders may be an underutilized, potentially powerful mechanism for improving OHCA survival. Future studies should investigate barriers and opportunities for increasing first responder interventions by these groups in OHCA.


Variation in community and ambulance care processes for out-of-hospital cardiac arrest during the COVID-19 pandemic: a systematic review and meta-analysis

Bystander cardiopulmonary resuscitation (BCPR), early defibrillation and timely treatment by emergency medical services (EMS) can double the chance of survival from out-of-hospital sudden cardiac arrest (OHCA). We investigated the effect of the COVID-19 pandemic on the pre-hospital chain of survival. 

We searched five bibliographical databases for articles that compared prehospital OHCA care processes during and before the COVID-19 pandemic. Random effects meta-analyses were conducted, and meta-regression with mixed-effect models and subgroup analyses were conducted where appropriate. The search yielded 966 articles; 20 articles were included in our analysis. OHCA at home was more common during the pandemic (OR 1.38, 95% CI 1.11-1.71, p = 0.0069). BCPR did not differ during and before the COVID-19 pandemic (OR 0.94, 95% CI 0.80-1.11, p = 0.4631), although bystander defibrillation was significantly lower during the COVID-19 pandemic (OR 0.65, 95% CI 0.48-0.88, p = 0.0107).

EMS call-to-arrival time was significantly higher during the COVID-19 pandemic (SMD 0.27, 95% CI 0.13-0.40, p = 0.0006). Resuscitation duration did not differ significantly between pandemic and pre-pandemic timeframes. The COVID-19 pandemic significantly affected prehospital processes for OHCA. These findings may inform future interventions, particularly to consider interventions to increase BCPR and improve the pre-hospital chain of survival.



Out-of-hospital cardiac arrest: Does rurality decrease chances of survival?

Geographical setting is seldomly taken into account when investigating out-of-hospital cardiac arrest (OHCA). It is a common notion that living in rural areas means a lower chance of fast and effective help when suffering a time-critical event. This retrospective cohort study investigates this hypothesis and compares across healthcare-divided administrative regions. We investigated incidence, EMS response time and 30-day survival according to area type and subsidiarily by healthcare-divided administrative region in Denmark.

The majority (71%) of 8,579 OHCAs were residential, and 53.2% of all arrests occurred in the most densely populated cell group amongst residential arrests. This group had a median EMS response time of six minutes, whereas the most sparsely populated group had a median of 10 minutes. Public arrests also had a median response time of six minutes.

Conclusion: Our study demonstrates that while EMS response times in Denmark are longer in the rural areas, there is no statistically significant decrease in survival compared to the most densely populated areas.



Pediatric defibrillation shocks alone do not cause heart damage in a porcine model

Automated external defibrillators (AEDs) use various shock protocols with different characteristics when deployed in pediatric mode. The aim of this study is to assess and compare the safety and efficacy of different AED pediatric protocols using novel experimental approaches.

Two defibrillation protocols (A and B) were assessed across two studies:

  • Protocol A: escalating (50-75-90 J) defibrillation waveform with higher voltage, shorter duration and equal phase durations.
  • Protocol B: non-escalating (50-50-50 J) defibrillation waveform with lower voltage, longer duration and unequal phase durations. Animals were randomized into two groups, receiving three shocks from Protocol A (50-75-90 J) or B (50-50-50 J).

Conclusions: There is no evidence that administration of clinically relevant shock sequences, without experimental confounders, result in significant myocardial damage in this model of pediatric resuscitation. Typical variations in AED pediatric mode settings do not affect defibrillation safety and efficacy.